Technical Field
The present disclosure relates to compounds, cosmetic or dermopharmaceutical compositions comprising the same, and methods for using the compounds or compositions for treating, protecting, and/or improving the condition and/or aesthetic appearance of skin, for example, treating, preventing, ameliorating, reducing and/or eliminating fine lines and/or wrinkles of skin, or improving the appearance of fine lines and/or wrinkles of skin, the methods comprising application of the disclosed compounds or compositions.
Background
Mammalian epidermis and its appendages (e.g., hair, nail, sebaceous and sweat glands) provide a barrier to keep harmful elements out of the body and essential body fluids in. As the first line of defense against the various physical traumas of the environment, the epidermis must protect itself as well as the underlying tissues. The epidermis is also exposed to mutagenic ultraviolet radiation. In nonhaired or sparsely haired regions such as most human skin, the epidermis is thicker than that of furred skin, and in these locations the skin functions primarily in a protective role. The constant assaults on the epidermis necessitate self-renewal, making the epidermis a prime example of an adult tissue that undergoes continual and rapid flux.
Aged skin differs from youthful skin both in appearance and in function. The aged epidermis lacks keratinocytes and is physically thinner, but mostly from effacement of the rete ridges. In addition to thinning, aging slows wound healing, prolongs epidermal turnover, and impairs barrier formation. The skin appears thin, wrinkled, bruised, and rough. Wrinkling and bruising can also result from aging-related changes in the dermis. The dermis, too, is characteristically thinner in aged persons. Aged fibroblasts are less likely to synthesize normal amounts of collagen, elastin, laminin glycosaminoglycans, and fibronectin. The dermis can, in such cases, lack elasticity, strength, vessel support, remodeling abilities, and ground substances. For example, rete ridges can be effaced, and basal cells can no longer display villous projections into the dermis. Epidermal cell turnover is reduced up to 50% in the aged as compared to youth. For example, melanocyte numbers can decrease 8-20% per decade. There are fewer Langerhans cells in the aged, and those present are often functionally impaired. Collagen synthesis decreases, for example, up to 30% within 4 years of menopause in women. The numbers of collagen and elastic fibers are also decreased. The dermis can also become less echogenic to ultrasounds, consistent with changes in collagen and elastic tissues.